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Abstract:

A moving picture coding apparatus 1 includes: a quantization matrix
holding unit (112) that holds a quantization matrix (WM) which has
already been transmitted in a parameter set and a matrix ID for
identifying the quantization matrix (WM), which are associated with each
other; and a variable length coding unit (111) that obtains the matrix ID
corresponding to the quantization matrix (WM) used for quantization from
the quantization matrix holding unit (112) and places the matrix ID in a
coded stream Str.

Claims:

1.-3. (canceled)

4. A coding method for coding a picture included in a moving picture by
using a quantization matrix, said coding method comprising: generating a
matrix ID identifying a quantization matrix different from a default
quantization matrix; coding the quantization matrix identified by the
matrix ID, in association with the matrix ID; coding a current picture
using the quantization matrix to generate data of the coded current
picture; and adding the matrix ID identifying the quantization matrix
used in said coding of the current picture, to the data of the coded
current picture, wherein the picture is made up of a luma component, a
first chroma component and a second chroma component, and wherein in said
coding of the current picture, when the quantization matrix for the first
chroma component is not coded and the quantization matrix for the second
chroma component is coded in said coding of the quantization matrix
identified by the matrix ID, the first chroma component of the current
picture is coded using the quantization matrix for the second chroma
component, instead of the default quantization matrix, as the
quantization matrix for the first chroma component of the current
picture, wherein a processor is configured to execute the generating
step, coding steps and adding step.

[0002] The present invention relates to a moving picture coding method for
coding moving pictures and generating streams and a moving picture
decoding method for decoding such coded streams, as well as the streams.

BACKGROUND ART

[0003] In the age of multimedia which integrally handles audio, video and
other pixel values, existing information media, i.e., newspaper,
magazine, television, radio, telephone and other means through which
information is conveyed to people, have recently come to be included in
the scope of multimedia. Generally, multimedia refers to something that
is represented by associating not only characters, but also graphics,
audio, and especially pictures and the like together. However, in order
to include the aforementioned existing information media into the scope
of multimedia, it appears as a prerequisite to represent such information
in digital form.

[0004] However, when calculating the amount of information contained in
each of the aforementioned information media as the amount of digital
information, while the amount of information per character is 1 to 2
bytes in the case of characters, the amount of information to be required
is 64 Kbits per second in the case of audio (telephone quality), and 100
Mbits per second in the case of moving pictures (current television
reception quality). Therefore, it is not realistic for the aforementioned
information media to handle such an enormous amount of information as it
is in digital form. For example, although video phones are already in the
actual use by using Integrated Services Digital Network (ISDN) which
offers a transmission speed of 64 Kbits/s to 1.5 Mbits/s, it is not
practical to transmit video of televisions and cameras directly through
ISDN.

[0005] Against this backdrop, information compression techniques have
become required, and moving picture compression techniques compliant with
H.261 and H.263 standards recommended by ITU-T (International
Telecommunication Union--Telecommunication Standardization Sector) are
employed for video phones, for example. Moreover, according to
information compression techniques compliant with the MPEG-1 standard, it
is possible to store picture information into an ordinary music CD
(compact disc) together with sound information.

[0006] Here, MPEG (Moving Picture Experts Group) is an international
standard on compression of moving picture signals standardized by ISO/IEC
(International Organization for Standardization, International
Electrotechnical Commission), and MPEG-1 is a standard for compressing
television signal information approximately into one hundredth so that
moving picture signals can be transmitted at a rate of 1.5 Mbit/s.
Furthermore, since a transmission speed achieved by the MPEG-1 standard
is a middle-quality speed of about 1.5 Mbit/s, MPEG-2, which was
standardized with a view to satisfying requirements for further improved
picture quality, allows data transmission equivalent in quality to
television broadcasting through which moving picture signals are
transmitted at a rate of 2 to 15 Mbit/s. Moreover, MPEG-4 was
standardized by the working group (ISO/IEC JTC1/SC29/WG11) which promoted
the standardization of MPEG-1 and MPEG-2. MPEG-4, which provides a higher
compression ratio than that of MPEG-1 and MPEG-2 and which enables an
object-based coding/decoding/operation, is capable of providing a new
functionality required in this age of multimedia. At the beginning stage
of standardization, MPEG-4 aimed at providing a low bit rate coding
method, but it has been extended as a standard supporting more general
coding that handles interlaced images as well as high bit rate coding.
Currently, an effort has been made jointly by ISO/IEC and ITU-T for
standardizing MPEG-4 AVC and ITU-T H.264 as picture coding methods of the
next generation that offer a higher compression ratio. As of August 2002,
a committee draft (CD) is issued for a picture coding method of the next
generation.

[0007] In general, in coding of a moving picture, the amount of
information is compressed by reducing redundancies in temporal and
spatial directions. Therefore, in inter picture prediction coding aiming
at reducing temporal redundancies, motion estimation and generation of a
predicative image are carried out on a block-by-block basis with
reference to forward or backward picture(s), and coding is then performed
on the difference value between the obtained predictive image and an
image in the current picture to be coded. Here, "picture" is a term
denoting one image. In the case of a progressive image, "picture" means a
frame, whereas it means a frame or fields in the case of an interlaced
image. Here, "interlaced image" is an image of a frame composed of two
fields which are separated in capture time. In coding and decoding of an
interlaced image, it is possible to handle one frame as a frame as it is,
as two fields, or as a frame structure or a field structure on a
per-block basis within the frame.

[0008] A picture to be coded using intra picture prediction without
reference to any pictures shall be referred to as an I picture. A picture
to be coded using inter picture prediction with reference to only one
picture shall be referred to as a P picture. And, a picture to be coded
using inter picture prediction with reference to two pictures at the same
time shall be referred to as a B picture. It is possible for a B picture
to refer to two pictures which can be arbitrarily combined from
forward/backward pictures in display order. Reference images (reference
pictures) can be determined for each block serving as a basic
coding/decoding unit. Distinction shall be made between such reference
pictures by calling a reference picture to be described earlier in a
coded bitstream as a first reference picture, and by calling a reference
picture to be described later in the bitstream as a second reference
picture. Note that as a condition for coding and decoding these types of
pictures, pictures used for reference are required to be already coded
and decoded.

[0009] P pictures and B pictures are coded using motion compensated inter
picture prediction. Coding by use of motion compensated inter picture
prediction is a coding method that employs motion compensation in inter
picture prediction coding. Unlike a method for performing prediction
simply based on pixel values in a reference picture, motion estimation is
a technique capable of improving prediction accuracy as well as reducing
the amount of data by estimating the amount of motion (hereinafter
referred to as "motion vector") of each part within a picture and further
by performing prediction in consideration of such amount of motion. For
example, it is possible to reduce the amount of data through motion
compensation by estimating motion vectors of the current picture to be
coded and then by coding prediction residuals between prediction values
obtained by shifting only the amount of the respective motion vectors and
the current picture to be coded. In this technique, motion vectors are
also recorded or transmitted in coded form, since motion vector
information is required at the time of decoding.

[0010] Motion vectors are estimated on a per-macroblock basis. More
specifically, a macroblock shall be previously fixed in the current
picture to be coded, so as to estimate motion vectors by finding the
position of the most similar reference block of such fixed macroblock
within the search area in a reference picture.

[0011] FIG. 1 is a diagram illustrating an example data structure of a
bitstream. As FIG. 1 shows, the bitstream has a hierarchical structure
such as below. The bitstream (Stream) is formed of more than one group of
pictures (GOP). By using GOPs as basic coding units, it becomes possible
to edit a moving picture as well as to make a random access. Each GOP is
made up of plural pictures, each of which is one of I picture, P picture,
and B picture. Each picture is further made up of plural slices. Each
slice, which is a strip-shaped area within each picture, is made up of
plural macroblocks. Moreover, each stream, GOP, picture, and slice
includes a synchronization signal (sync) for indicating the ending point
of each unit and a header (header) which is data common to said each
unit.

[0012] Note that when data is carried not in a bitstream being a sequence
of streams, but in a packet and the like being a piecemeal unit, the
header and the data portion, which is the other part than the header, may
be carried separately. In such a case, the header and the data portion
shall not be incorporated into the same bitstream, as shown in FIG. 1. In
the case of a packet, however, even when the header and the data portion
are not transmitted contiguously, it is simply that the header
corresponding to the data portion is carried in another packet.
Therefore, even when the header and the data portion are not incorporated
into the same bitstream, the concept of a coded bitstream described with
reference to FIG. 1 is also applicable to packets.

[0013] Generally speaking, the human sense of vision is more sensitive to
the low frequency components than to the high frequency components.
Furthermore, since the energy of the low frequency components in a
picture signal is larger than that of the high frequency components,
picture coding is performed in order from the low frequency components to
the high frequency components. As a result, the number of bits required
for coding the low frequency components is larger than that required for
the high frequency components.

[0014] In view of the above points, the existing coding methods use larger
quantization steps for the high frequency components than for the low
frequency components when quantizing transformation coefficients, which
are obtained by orthogonal transformation, of the respective frequencies.
This technique has made it possible for the conventional coding methods
to achieve a large increase in compression ratio with a small loss of
picture quality from the standpoint of viewers.

[0015] Meanwhile, since quantization step sizes of the high frequency
components with regard to the low frequency components depend on picture
signal, a technique for changing the sizes of quantization steps for the
respective frequency components on a picture-by-picture basis has been
conventionally employed. A quantization matrix is used to derive
quantization steps of the respective frequency components. FIG. 2 shows
an example quantization matrix. In this drawing, the upper left component
is a direct current component, whereas rightward components are
horizontal high frequency components and downward components are vertical
high frequency components. The quantization matrix in FIG. 2 also
indicates that a larger quantization step is applied to a larger value.
Usually, it is possible to use different quantization matrices for each
picture, and the matrix to be used is described in each picture header.
Therefore, even if the same quantization matrix is used for all the
pictures, it is described in each picture header and carried one by one.

[0016] Meanwhile, current MPEG-4 AVC does not include quantization matrix
as in MPEG-2 and MPEG-4. This results in difficulty in achieving optimal
subjective quality in the current MPEG-4 AVC coding scheme and other
schemes using uniform quantization in all DCT or DCT-like coefficients.
When such quantization matrix scheme is introduced, we have to allow the
current provision of MPEG-4 AVC or other standards to carry the
quantization matrices, in consideration of compatibility with the
existing standards.

[0017] Additionally, because of the coding efficiency improvement, MPEG-4
AVC has been able to provide the potential to be used in various
application domains. The versatility warrants the use of different sets
of quantization matrices for different applications; different sets of
quantization matrices for different color channels, etc. Encoders can
select different quantization matrices depending on application or image
to be coded. Because of that, we must develop an efficient quantization
matrix definition and loading protocol to facilitate the flexible yet
effective transmission of quantization matrix information.

DISCLOSURE OF INVENTION

[0018] The present invention has been conceived in view of the above
circumstances, and it is an object of the present invention to provide a
moving picture coding method and a moving picture decoding method that
are capable of reducing the amount of data to be coded and improving
coding efficiency.

[0019] In order to achieve the above objective, the moving picture coding
method according to the present invention is a moving picture coding
method for coding, on a block-by-block basis, each picture that makes up
a moving picture, and generating a coded stream, the method comprising:
transforming, on a block-by-block basis, each picture into coefficients
representing spatial frequency components; quantizing the coefficients
using a quantization matrix; generating identification information that
identifies the quantization matrix used for quantization; and placing the
identification information in the coded stream in predetermined units.

[0020] According to the above method, since there is no need to describe a
quantization matrix used for quantization in the predetermined units, for
example, picture, slice, macroblock or the like, it becomes possible to
reduce the amount of data to be coded and thus perform coding of the data
efficiently.

[0021] In the above method, the quantization matrix may be stored into the
coded stream at a location that can be accessed before the data obtained
by quantizing the coefficients using said quantization matrix can be
retrieved.

[0022] Here, in the storage, the quantization matrix may be stored into a
first parameter set or a second parameter set for holding information
necessary for decoding, the first parameter set or the second parameter
set being placed in the coded stream at the location that can be accessed
before the data obtained by quantizing the coefficients using the
quantization matrix can be retrieved.

[0023] According to the above method, it becomes possible to use, for
decoding, the quantization matrix identified by the identification
information.

[0024] In the above-mentioned moving picture coding method, a flag may be
placed in the coded stream in predetermined units, the flag indicating
switching between the quantization matrix identifiable by the
identification information and a default quantization matrix.

[0025] According to the above method, it becomes possible to indicate
switching between the quantization matrix identifiable by the
identification information and the default quantization matrix, using the
identification information.

[0026] The moving picture decoding method according to the present
invention is a moving picture decoding method for decoding a coded stream
obtained by coding each picture that makes up a moving picture through
orthogonal transformation and quantization on a block-by-block basis, the
method comprising: holding at least one quantization matrix; extracting,
in predetermined units, identification information that identifies a
quantization matrix used for quantization, from the coded stream;
identifying the quantization matrix based on the identification
information from the at least one held quantization matrix; performing
inverse quantization of each coded picture on a block-by-block basis
using the identified quantization matrix; and decoding the coded picture
by performing inverse orthogonal transformation on inverse quantized
coefficients indicating spatial frequency components.

[0027] According to the above method, it becomes possible to decode a
coded stream in which only the matrix ID for identifying the quantization
matrix used for quantization is placed in predetermined units, such as
picture, slice, macroblock or the like, while the quantization matrix has
previously been carried separately.

[0028] In the above-mentioned moving picture decoding method, at least one
quantization matrix may be extracted from the coded stream, and in the
holding, the quantization matrix extracted from the coded stream may be
held.

[0029] Here, in the extracting, the quantization matrix may be extracted
from a first parameter set or a second parameter set in which information
necessary for decoding is stored.

[0030] According to the above method, it becomes possible to use the
quantization matrix identified by the identification information.

[0031] In the above-mentioned moving picture decoding method, a flag may
be extracted from the coded stream in predetermined units, the flag
indicating switching between the quantization matrix identified by the
identification information and a default quantization matrix, and in the
identifying, the quantization matrix identified by the identification
information and the default quantization matrix may be switched.

[0032] According to the above method, it becomes possible to switch
between the quantization matrix identified by the identification
information and the default quantization matrix, based on the flag.

[0033] In the above method, each picture is made up of luma components and
two types of chroma components, and in the identifying, in the case where
there is no quantization matrix for chroma components in the quantization
matrices identified based on the identification information, a
quantization matrix for luma components may be identified as the
quantization matrix to be used.

[0034] Also, each picture is made up of a luma component and two types of
chroma components, and in the identifying, in the case where there is no
quantization matrix for chroma components of a type corresponding to
current decoding in the quantization matrices identified based on the
identification information, a quantization matrix for another type of
chroma components may be identified as the quantization matrix to be
used.

[0035] According to the above method, it becomes possible to decode a
coded stream even if there is no quantization matrix for chroma.

[0036] Furthermore, not only is it possible to embody the present
invention as a moving picture coding method and a moving picture decoding
method, but also as a moving picture coding apparatus and a moving
picture decoding apparatus that include, as steps, the characteristic
units included in such moving picture coding method and moving picture
decoding method. It is also possible to embody them as programs that
cause a computer to execute these steps, or as streams coded by the
moving picture coding method. It should be noted that such programs and
coded streams can be distributed on a recording medium such as a CD-ROM
and via a transmission medium such as the Internet.

[0037] As is obvious from the above explanation, according to the moving
picture coding method and the moving picture decoding method of the
present invention, it becomes possible to reduce an amount of data to be
coded and achieve efficient coding and decoding.

BRIEF DESCRIPTION OF DRAWINGS

[0038] These and other objects, advantages and features of the invention
will become apparent from the following description thereof taken in
conjunction with the accompanying drawings that illustrate a specific
embodiment of the invention. In the Drawings:

[0039] FIG. 1 is a diagram illustrating an example data structure of a
bitstream;

[0040] FIG. 2 is a diagram showing an example quantization matrix;

[0041]FIG. 3 is a block diagram showing a structure of a moving picture
coding apparatus that embodies the moving picture coding method according
to the present invention;

[0043] FIG. 5 is a diagram showing a part of a structure of a sequence
parameter set;

[0044]FIG. 6 is a diagram showing a part of a structure of a picture
parameter set;

[0045]FIG. 7 is a diagram showing an example description of quantization
matrices in a parameter set;

[0046]FIG. 8 is a flowchart showing operations for placing a matrix ID;

[0047]FIG. 9 is a block diagram showing a structure of a moving picture
decoding apparatus that embodies the moving picture decoding method
according to the present invention;

[0048]FIG. 10 is a flowchart showing operations for identifying a
quantization matrix;

[0049]FIG. 11 is a flowchart showing operations for identifying a
quantization matrix to be used for chroma components;

[0050] FIG. 12 is a diagram showing correspondence between quantization
matrices carried as separate data and quantization matrices to be used
for sequences;

[0051] FIGS. 13A to 13C are diagrams illustrating a recording medium that
stores a program for realizing, by a computer system, the moving picture
coding method and the moving picture decoding method according to the
above embodiments, and particularly, FIG. 13A is a diagram illustrating
an example physical format of a flexible disk as a main body of a
recording medium, FIG. 13B is a full appearance of the flexible disk
viewed from the front thereof, a cross-sectional view thereof and the
flexible disk itself, and FIG. 13C is a diagram illustrating a structure
for recording and reproducing the above program on and from the flexible
disk;

[0052]FIG. 14 is a block diagram showing an overall configuration of a
content supply system that embodies a content distribution service;

[0054]FIG. 16 is a block diagram showing an inner structure of the
cellular phone; and

[0055]FIG. 17 is a diagram showing an overall configuration of a digital
broadcasting system.

BEST MODE FOR CARRYING OUT THE INVENTION

[0056] The embodiments of the present invention are described by referring
to diagrams.

First Embodiment

[0057]FIG. 3 is a block diagram showing the structure of a moving picture
coding apparatus that embodies the moving picture coding method of the
present invention.

[0058] A picture coding apparatus 1 is an apparatus for performing
compression coding on an input picture signal Vin and outputting a coded
stream Str which has been coded into a bitstream by performing variable
length coding and the like. As shown in FIG. 3, such picture coding
apparatus 3 is comprised of a motion estimation unit 101, a motion
compensation unit 102, a subtraction unit 103, an orthogonal
transformation unit 104, a quantization unit 105, an inverse quantization
unit 106, an inverse orthogonal transformation unit 107, an addition unit
108, a picture memory 109, a switch 110, a variable length coding unit
111 and a quantization matrix holding unit 112.

[0059] The picture signal Vin is inputted to the subtraction unit 103 and
the motion estimation unit 101. The subtraction unit 103 calculates
residual pixel values between each image in the input picture signal Vin
and each predictive image, and outputs the calculated residual pixel
values to the orthogonal transformation unit 104. The orthogonal
transformation unit 104 transforms the residual pixel values into
frequency coefficients, and outputs them to the quantization unit 105.
The quantization unit 105 quantizes the inputted frequency coefficients
using inputted quantization matrix WM, and outputs the resulting
quantized values Qcoef to the variable length coding unit 111.

[0060] The inverse quantization unit 106 performs inverse quantization on
the quantized values Qcoef using the inputted quantization matrix WM, so
as to turn them into the frequency coefficients, and outputs them to the
inverse orthogonal transformation unit 107. The inverse orthogonal
transformation unit 107 performs inverse frequency transformation on the
frequency coefficients so as to transform them into residual pixel
values, and outputs them to the addition unit 108. The addition unit 108
adds the residual pixel values and each predictive image outputted from
the motion estimation unit 102, so as to form a decoded image. The switch
110 turns ON when it is indicated that such decoded image should be
stored, and such decoded image is to be stored into the picture memory
109.

[0061] Meanwhile, the motion estimation unit 101, which receives the
picture signal Vin on a macroblock basis, detects an image area closest
to an image signal in such inputted picture signal Vin within a decoded
picture stored in the picture memory 109, and determines motion vector(s)
MV indicating the position of such area. Motion vectors are estimated for
each block, which is obtained by further dividing a macroblock. When this
is done, it is possible to use more than one picture as reference
pictures. Here, since a plurality of pictures can be used as reference
pictures, identification numbers (reference indices Index) to identify
the respective reference pictures are required on a block-by-block basis.
With the use of the reference indices Index, it is possible to identify
each reference picture by associating each picture stored in the picture
memory 109 with the picture number designated to such each picture.

[0062] The motion compensation unit 102 selects, as a predictive image,
the most suitable image area from among decoded pictures stored in the
picture memory 109, using the motion vectors detected in the above
processing and the reference indices Index.

[0063] The quantization matrix holding unit 112 holds the quantization
matrix WM which has already been carried as a part of a parameter set and
the matrix ID that identifies this quantization matrix WM in the manner
in which they are associated with each other.

[0064] The variable length coding unit 111 obtains, from the quantization
matrix holding unit 112, the matrix ID corresponding to the quantization
matrix WM used for quantization. The variable length coding unit 111 also
performs variable length coding on the quantization values Qcoef, the
matrix IDs, the reference indices Index, the picture types Ptype and the
motion vectors MV so as to obtain a coded stream Str.

[0065]FIG. 4 is a diagram showing the correspondence between sequence
parameter sets and picture parameter sets and pictures. FIG. 5 is a
diagram showing a part of a structure of a sequence parameter set, and
FIG. 6 is a diagram showing a part of a structure of a picture parameter
set. While a picture is made up of slices, all the slices included in the
same picture have identifiers indicating the same picture parameter set.

[0066] In MPEG-4 AVC, there is no concept of a header, and common data is
placed at the top of a sequence under the designation of a parameter set.
There are two types of parameter sets, a picture parameter set PPS that
is data corresponding to the header of each picture, and a sequence
parameter set SPS corresponding to the header of a GOP or a sequence in
MPEG-2. A sequence parameter set SPS includes the number of pictures that
are available as reference pictures, image size and the like, while a
picture parameter set PPS includes a type of variable length coding
(switching between Huffman coding and arithmetic coding), default values
of quantization matrices, the number of reference pictures, and the like.

[0067] An identifier is assigned to a sequence parameter set SPS, and to
which sequence a picture belongs is identified by specifying this
identifier in a picture parameter set PPS. An identifier is also assigned
to a picture parameter set PPS, and which picture parameter set PPS is to
be used is identified by specifying this identifier in a slice.

[0068] For example, in the example shown in FIG. 4, a picture #1 includes
the identifier (PPS=1) of a picture parameter set PPS to be referred to
by a slice included in the picture #1. The picture parameter set PPS #1
includes the identifier (SPS=1) of a sequence parameter set to be
referred to.

[0069] Furthermore, the sequence parameter set SPS and the picture
parameter set PPS respectively include flags 501 and 601 indicating
whether or not quantization matrices are carried as shown in FIG. 5 and
FIG. 6, and in the case where the quantization matrices are to be
carried, quantization matrices 502 and 602 are respectively described
therein.

[0071]FIG. 7 is a diagram showing an example description of quantization
matrices in a parameter set.

[0072] Since a picture signal Vin consists of luma components and two
types of chroma components, it is possible to use different quantization
matrices for luma components and two types of chroma components
separately when performing quantization. It is also possible to use
different quantization matrices for intra-picture coding and
inter-picture coding separately.

[0073] Therefore, for example, as shown in FIG. 7, it is possible to
describe quantization matrices for a unit of quantization, luma
components and two types of chroma components, and intra-picture coding
and inter-picture coding, respectively.

[0074] The operations for placing matrix IDs in the above-structured
moving picture coding apparatus are explained. FIG. 8 is a flowchart
showing the operations for placing a matrix ID.

[0076] On the other hand, in the case where the obtained quantization
matrix WM is not held in the quantization matrix holding unit 112 (NO in
Step S102), the quantization matrix holding unit 112 generates the matrix
ID for this quantization matrix WM (Step S105). Then, the quantization
matrix holding unit 112 holds this quantization matrix WM and the matrix
ID in the manner in which they are associated with each other (Step
S106). The variable length coding unit 111 places the generated matrix ID
in predetermined units (for example, per picture, slice or macroblock)
(Step S107). The variable length coding unit 111 describes the generated
matrix ID and the quantization matrix WM in the parameter set (Step
S108). Note that the parameter set in which these matrix ID and
quantization matrix WM are described is carried earlier, in a coded
stream Str, than the predetermined units (that is, coded data quantized
using this quantization matrix WM) to which this matrix ID is placed.

[0077] As described above, since quantization matrices WM are described in
a parameter set and carried while only the matrix ID that identifies the
quantization matrix WM used in predetermined units (for example, per
picture, slice or macroblock) is placed therein, there is no need to
describe the quantization matrix WM used in every predetermined unit.
Therefore, it becomes possible to reduce the amount of data to be coded
and achieve efficient coding.

[0078] Note that it is possible to update a quantization matrix WM carried
in a sequence parameter set SPS and carry the updated one (with the same
matrix ID) in a picture parameter set PPS. In this case, the updated
quantization matrix WM is used only when the picture parameter set PPS is
referenced.

[0079] It is also possible to include in a coded stream a flag indicating
switching between the default quantization matrix WM and the quantization
matrix WM identified by a matrix ID. In this case, the default
quantization matrix WM is replaced with the quantization matrix WM
identified by the matrix ID according to the flag.

[0080]FIG. 9 is a block diagram showing a structure of a moving picture
decoding apparatus that embodies the moving picture decoding method
according to the present invention.

[0081] The moving picture decoding apparatus 2 is an apparatus that
decodes a coded stream obtained by the coding by the moving picture
coding apparatus 1 as described above, and includes a variable length
decoding unit 201, a quantization matrix holding unit 202, a picture
memory 203, a motion compensation unit 204, an inverse quantization unit
205, an inverse orthogonal transformation unit 206 and an addition unit
207.

[0083] The quantization matrix holding unit 202 associates the
quantization matrix WM which has already been carried in a parameter set
with the matrix ID that identifies this quantization matrix WM, and holds
them.

[0084] The quantized values Qcoef, reference indices Index and motion
vectors MV are inputted to the picture memory 203, the motion
compensation unit 204 and the inverse quantization unit 205, and decoding
processing is performed on them. The operations for the decoding are same
as those in the moving picture coding apparatus 1 shown in FIG. 3.

[0085] Next, the operations for identifying a quantization matrix in the
above-structured moving picture decoding apparatus are explained. FIG. 10
is a flowchart showing the operations for identifying a quantization
matrix.

[0087] As described above, while a quantization matrices WM are described
in a parameter set and carried, it is possible, in predetermined units
(for example, per picture, per slice or per macroblock), to decode a
coded stream in which only the matrix ID that identifies the used
quantization matrix WM is placed.

[0088] Note that quantization matrices WM are described in a parameter set
and carried in the present embodiment but the present invention is not
limited to such case. For example, quantization matrices may be
previously transmitted separately from a coded stream.

[0089] By the way, since a picture signal Vin is made up of luma
components and two types of chroma components as described above, it is
possible to use different quantization matrices separately for luma
components and two types of chroma components for quantization. It is
also possible to use an uniform quantization matrix for all the
components.

[0090] Next, the operations for identifying quantization matrices to be
used for chroma components are explained. FIG. 11 is a flowchart showing
the operations for identifying quantization matrices to be used for
chroma components.

[0091] The variable length decoding unit 201 judges whether or not there
is a quantization matrix for chroma components of the type corresponding
to the current decoding among the quantization matrices WM identified as
mentioned above (Step S301). For example, in the case where a quantized
value Qcoef to be decoded is a first chroma component, it judges whether
or not there is a quantization matrix for the first chroma components. In
the case where a quantized value Qcoef to be decoded is a second chroma
component, it judges whether or not there is a quantization matrix for
the second chroma components. Here, if there is a quantization matrix for
the corresponding type of chroma components (YES in Step S301), it
outputs the corresponding chroma quantization matrix to the inverse
quantization unit 205 as a matrix to be used (Step S302).

[0092] On the other hand, if there is no such corresponding chroma
quantization matrix (NO in Step S301), the variable length decoding unit
201 judges whether or not there is a quantization matrix for another type
of chroma components (Step S303). For example, in the case where a
quantized value Qcoef to be decoded is a first chroma component, it
judges whether or not there is a quantization matrix for the second
chroma components. In the case where a quantized value Qcoef to be
decoded is a second chroma component, it judges whether or not there is a
quantization matrix for the first chroma components. Here, if there is a
corresponding quantization matrix for another type of chroma components
(YES in Step S303), it outputs the quantization matrix for another type
of chroma components to the inverse quantization unit 205 as a matrix to
be used (Step S304). On the other hand, if there is no quantization
matrix for another type of chroma components (NO in Step S303), it
outputs the quantization matrix for the luma components to the inverse
quantization unit 205 as a matrix to be used (Step S305).

[0093] As a result, it becomes possible to decode a coded stream even if
there is no chroma quantization matrix.

Second Embodiment

[0094] The key points in the present embodiment are as follows.

[0095] 1. If there are multiple sequence-level stream description data
structures selectable by a different part of a video bitstream, the
quantization matrix shall be carried in a data structure separate from
any of the sequence header data structure.

[0096] 2. Multiple quantization matrices customized by users are defined
at the beginning of a sequence video stream. The quantization matrices
shall be selectable at different pictures at different locations in a
bitstream. MPEG-2 uses quantization matrix scheme but it did not use a
set of matrices from which one of them can be selected. It has to reload
a new matrix when a quantization matrix is updated.

[0097] 3. How frequent the update would be performed is specified as
syntax elements to apply the quantization updates, so that the
quantization matrix update scheme is compatible with the above
description. In the scheme of the present embodiment, MPEG-2 single
effective quantization matrix and later update is only a special case of
this update scheme.

[0098] Next, the overview of the present embodiment is described.

[0099] In some video coding standards, there may be several segments in a
sequence that are encoded using different encoding configurations, and as
such, they require different sequence or segment header descriptors for
each segment in the sequence. As transmitting quantization matrix takes
considerable number of bits, we place all quantization matrices used in a
sequence somewhere separate from any of the sequence or segment headers.
For segments of the sequence that use different sets of quantization
matrices, it only needs to reference the quantization matrices, such as
an identification number, rather than transmitting the matrix from an
encoder to decoders every time the matrix is used, which is the mechanism
that MPEG-2 has used.

[0100] All the quantization matrices that are not specified in the video
coderc's specification should be defined and grouped together. The
segment or block of the bitstream that carries these quantization
matrices should be placed at the beginning of the bitstream of a sequence
before any encoded video data are transmitted. As choices that can be
made by different video codec standards, those quantization matrices can
be included as part of the video elementary stream, or can be carried
out-of-band, such as in transport stream or in packets or in files
separate from the main body of the video stream.

[0101] In many codec specifications, such as MPEG-2, MPEG-4, there are
lower-level data structures contained in a sequence segment, which
organizes video data into "group of pictures", pictures, slices, layers,
macroblocks, so on. If a sequence segment header or descriptor references
more than one set of quantization matrices, the choices of which one set
to use will be left to lower level data structure to specify. This will
be discussed later in this disclosure.

[0102] For those sequence segments that references more than one set of
quantization matrix, all the quantization matrices are carried in the
beginning of a sequence. The decoder that has received all the
quantization matrices shall keep these quantization in its memory in a
way that, when the decoder references a particular quantization matrix,
all the look up tables, if there are any, associated with the
quantization matrices will be ready to use. In implementing the
specification of the syntax, the capacity of the decoders has to be taken
into consideration to fit the capacity limit into the application
requirement the decoders fit to. Therefore, the number of quantization
matrices available in any given time shall not exceed a certain range.

[0103] In case that the decoder capacity does not allow storage of more
than one set of quantization matrices, whenever a new set of quantization
matrices become needed, the previously stored quantization matrix set has
to be removed from decoder memory before the new one can be stored and
become effective. This scenario becomes the same as that MPEG-2 has used
in its specification.

[0104] FIG. 12 is a diagram showing correspondence between quantization
matrices carried as separate data and quantization matrices to be used
for a sequence.

[0105] In the example shown in FIG. 12, it is described that quantization
matrices Q-matrix 1 and Q-matrix 3 are used in a sequence SEQ1. It is
also described that quantization matrices Q-matrix 2, Q-matrix 4 and
Q-matrix 5 are used in a sequence SEQ2, and a quantization matrix
Q-matrix 4 is used in a sequence SEQ3.

[0106] Next, features in the syntax to support the use of quantization
matrix are explained.

[0107] Quantization matrix can be fixed for an entire sequence or
programs.

[0108] But the more flexible way to achieve better quality is to allow
quantization scheme and quantization matrices to be changed dynamically.
In such case, the issue is at what data level that kind of changes should
be allowed. It is understood that depending on complexity allowed by an
application domain, there will be restriction on the number of
quantization matrix sets to be allowed at what data levels.

[0109] For all the stream data structure levels, that is, from sequence,
segments, pictures, slices, to macroblocks, (macroblock has been used in
almost all codec standards to mean 16×16 block of pixels, however,
this dimension may change in proprietary or future codecs) we have in the
bitstream a 6-bit flag containing the following bits (as shown in Table
1) to indicate what types of quantization are allowed to change at from
one immediate lower level data to another. For example, in MPEG-4 AVC,
the immediate lower level of "Sequence" is "Picture" and the immediate
lower level of "Picture" is "Slice".

[0110] Note that when only Bit A is set and Bit B is not set, Bit C cannot
be set. Similarly, when only Bit D is set and Bit E is not set, Bit F
cannot be set.

[0111] When Bit B and Bit C are both set, it means quantization matrix set
can change from one to another. One quantization matrix set contains one
matrix per block coding mode. The block coding mode can be
intra-prediction of certain direction, inter-predicted block, a
bi-predicted block etc.

[0112] Bit C and Bit F indicate changes of quantization scheme or
quantization matrix set or both. If the bit for 8×8 non-uniform
quantization with quantization matrix is set in the Sequence level in
MPEG-4 AVC, the quantization matrix used in one "Picture" data can be
different from other "Picture" data.

[0113] At the highest level of data syntax, such as sequence header, if
quantization matrix scheme is used, a default quantization set will be
specified.

[0114] When Bit C or Bit F is set for a data level, there will a flag for
each of the lower level data headers to indicate whether the default
quantization matrix set will be used in these levels.

[0115] If the flag is positive in a lower data header, a new default
quantization set for this data level will be defined and a 6-bit flag
will be used at this data level to indicate whether the default will be
changed in the further lower data level. This is followed in all data
levels until the lowest level or the lowest level permitted by
application requirement.

[0116] When Bit C or Bit F is not set, there will not be this flag in
lower data headers, and the default will be automatically assumed.

[0117] There can be restrictions applicable in this recursive signaling
method for transmitting information on quantization schemes, for example,
restriction by the frequency of quantization matrix changes that has to
be capped under a certain rate.

[0119] In a video coding specification using non-uniform quantization
matrix scheme, there may be several predefined matrices in a video codec
specification. These default or prescribed matrices are known by
compliant decoders and therefore there is no need to transfer the
matrices to decoders. In similar way, these quantization matrices can be
referenced in the same way as described above. When prescribed matrices
are available, decoder shall add received customized matrices into its
pool of quantization matrices. As described above, distinctive
quantization matrices are indexed by identification numbers, which are
assigned by encoder and transmitted to decoders.

[0120] In organizing the quantization matrices in bitstream syntax, the
quantization of the same size can be grouped together. Information
regarding whether a matrix should be used for inter-coded blocks or
intra-coded blocks, or whether a matrix should be used for luma or chroma
can also be noted in their attributes.

[0121] Next, update of a quantization matrix is explained.

[0122] Video codec bitstream syntax can allow quantization matrices
already known to decoders to be added or updated.

[0123] When a quantization matrix is associated with a new identification
number, this matrix is taken as a new quantization matrix and can be
referenced by the new identification number. When the identification
number has already been associated with a quantization matrix, the
existing quantization matrix will be modified at decoders with the new
matrix. Only quantization matrix of the same size as the old one can
replace an old matrix. Encoder is responsible in keeping track of the
active quantization matrices. During transmission of the updated
quantization matrices, only the quantization matrix that needs to be
updated is defined in the network packets.

[0125] In MPEG-4 AVC, all video data and headers are packed into a
bitstream layer called Network Abstract Layer (NAL). NAL is a sequence of
many NAL units. Each NAL unit carries certain type of video data or data
headers.

[0126] MPEG-4 AVC also defines several picture data groups under one data
hierarchy. The hierarchy starts at Sequence, which is described by
Sequence Parameter Set. A "Sequence" can have pictures using different
Picture Parameter Sets. Under "Picture", there are slices, where slices
have slice headers. A slice typically has many 16×16 blocks of
pixels, called macroblocks.

[0127] When we introduce quantization matrix scheme into MPEG-4 AVC, we
can have user defined quantization matrices or encoder-provided matrices
be carried over NAL units. The use of NAL units can be implemented in
three different ways.

[0128] (1) One NAL unit carries all the matrix information (including
quantization tables) associated with each of the matrices.

[0129] (2) Several NAL units each carries certain type of quantization
matrices and their information.

[0130] (3) Each NAL unit carries the definition of one quantization
matrix.

[0131] In the case (1) and (2), the NAL units will also provide the total
number of quantization matrices. In case 3, the total number of
user-defined quantization matrices is not explicitly given by the video
elementary stream. Both encoder and decoder must count the total as they
go. An example of case 2 is when 4×4 quantization matrices and
8×8 quantization matrices are grouped and each is carried in a NAL.

[0132] In the sequence parameter set, MPEG-4 shall specify which
quantization matrices it will use. It will define the 6-bit flag to
indicate what quantization scheme will be used and whether it is allowed
to change in the next level that is picture level, whose header is
Picture Parameter Set.

[0133] The sequence parameter set that references a subset of the defined
quantization matrices shall list all the quantization matrix IDs, which
includes those default to the video codec specification, and those
defined specifically for the content by codec operators. Sequence
parameter sets can carry some common quantization parameters. A sequence
parameter set can declare a set of default quantization matrices each for
inter and intra prediction for each 8×8 and 4×4 block for
luma and inter and intra for chroma. Picture parameter set, slice header,
and macroblock level, however, can declare their own set of quantization
matrices to override higher level specification. However these
quantization matrices must be available in the Sequence Parameter Set
currently available.

[0134] When quantization matrices are carried over NAL units, they can be
transmitted at the beginning of the bitstream of the sequence. The
position can be that it can either be located after or before the NAL
unit carrying Sequence Parameter Sets. After the initial definition,
additional customized quantization matrices can be inserted into
bitstream to update or add new ones. The operation whether to add or to
update is determined by the quantization matrix ID. If the ID exists, it
is update. If the ID does not exist, the matrix will be added into the
matrix pool.

Third Embodiment

[0135] Furthermore, if a program for realizing the moving picture coding
method and the moving picture decoding method as shown in each of the
aforementioned embodiments are recorded on a recording medium such as a
flexible disk, it becomes possible to easily perform the processing
presented in each of the above embodiments in an independent computer
system.

[0136] FIGS. 13A, 13B, and 13C are illustrations for realizing the moving
picture coding method and the moving picture decoding method described in
each of the above embodiments, using a program stored in a storage medium
such as a flexible disk in a computer system.

[0137]FIG. 13B shows an external view of a flexible disk viewed from the
front, its schematic cross-sectional view, and the flexible disk itself,
while FIG. 13A illustrates an example physical format of the flexible
disk as a recording medium itself. The flexible disk FD is contained in a
case F, and a plurality of tracks Tr are formed concentrically on the
surface of the flexible disk FD in the radius direction from the
periphery, each track being divided into 16 sectors Se in the angular
direction. Therefore, in the flexible disk storing the above-mentioned
program, the program is recorded in an area allocated for it on the
flexible disk FD.

[0138] Meanwhile, FIG. 13C shows the structure required for recording and
reading out the program on and from the flexible disk FD. When the
program realizing the above moving picture coding method and moving
picture decoding method is to be recorded onto the flexible disk FD, such
program shall be written by the use of the computer system Cs via a
flexible disk drive FDD. Meanwhile, when the moving picture coding method
and the moving picture decoding method are to be constructed in the
computer system Cs through the program for realizing these methods on the
flexible disk FD, the program shall be read out from the flexible disk FD
via the flexible disk drive FDD and then transferred to the computer
system Cs.

[0139] The above description is given on the assumption that a recording
medium is a flexible disk, but an optical disc may also be used. In
addition, the recording medium is not limited to this, and any other
medium such as an IC card and a ROM cassette capable of recording a
program can also be used.

Fourth Embodiment

[0140] The following describes application examples of the moving picture
coding method and the moving picture decoding method as shown in the
above embodiments as well as a system using them.

[0141]FIG. 14 is a block diagram showing an overall configuration of a
content supply system ex100 that realizes a content distribution service.
The area for providing a communication service is divided into cells of
desired size, and base stations ex107˜ex110, which are fixed
wireless stations, are placed in the respective cells.

[0142] In this content supply system ex100, devices such as a computer
ex111, a PDA (Personal Digital Assistant) ex112, a camera ex113, a
cellular phone ex114, and a camera-equipped cellular phone ex115 are
respectively connected to the Internet ex101 via an Internet service
provider ex102, a telephone network ex104, and the base stations
ex107˜ex110.

[0143] However, the content supply system ex100 is not limited to the
combination as shown in FIG. 14, and may be connected to a combination of
any of them. Also, each of the devices may be connected directly to the
telephone network ex104, not via the base stations ex107˜ex110,
which are fixed wireless stations.

[0144] The camera ex113 is a device such as a digital video camera capable
of shooting moving pictures. The cellular phone may be a cellular phone
of a PDC (Personal Digital Communications) system, a CDMA (Code Division
Multiple Access) system, a W-CDMA (Wideband-Code Division Multiple
Access) system or a GSM (Global System for Mobile Communications) system,
a PHS (Personal Handyphone system) or the like, and may be any one of
these.

[0145] Furthermore, a streaming server ex103 is connected to the camera
ex113 via the base station ex109 and the telephone network ex104, which
enables live distribution or the like based on coded data transmitted by
the user using the camera ex113. Either the camera ex113 or a server and
the like capable of performing data transmission processing may code the
shot data. Also, moving picture data shot by a camera ex116 may be
transmitted to the streaming server ex103 via the computer ex111. The
camera ex116 is a device such as a digital camera capable of shooting
still pictures and moving pictures. In this case, either the camera ex116
or the computer ex111 may code the moving picture data. In this case, an
LSI ex117 included in the computer ex111 or the camera ex116 performs
coding processing. Note that software for picture coding and decoding may
be integrated into a certain type of storage medium (such as a CD-ROM, a
flexible disk and a hard disk) that is a recording medium readable by the
computer ex111 and the like. Furthermore, the camera-equipped cellular
phone ex115 may transmit the moving picture data. This moving picture
data is data coded by an LSI included in the cellular phone ex115.

[0146] In this content supply system ex100, content (e.g. a music live
video) which has been shot by the user using the camera ex113, the camera
ex116 or the like is coded in the same manner as the above-described
embodiments and transmitted to the streaming server ex103, and the
streaming server ex103 makes stream distribution of the content data to
clients at their requests. The clients here include the computer ex111,
the PDA ex112, the camera ex113, the cellular phone ex114 and so forth
capable of decoding the above coded data. The content supply system ex100
with the above configuration is a system that enables the clients to
receive and reproduce the coded data and realizes personal broadcasting
by allowing them to receive, decode and reproduce the data in real time.

[0147] The moving picture coding apparatus and moving picture decoding
apparatus presented in the above embodiments can be used for coding and
decoding to be performed in each of the devices making up the above
system.

[0148] An explanation is given of a cellular phone as an example.

[0149]FIG. 15 is a diagram showing the cellular phone ex115 that employs
the moving picture coding method and the moving picture decoding method
explained in the above embodiments. The cellular phone ex115 has an
antenna ex201 for transmitting/receiving radio waves to and from the base
station ex110, a camera unit ex203 such as a CCD camera capable of
shooting video and still pictures, a display unit ex202 such as a liquid
crystal display for displaying the data obtained by decoding video and
the like shot by the camera unit ex203 and video and the like received by
the antenna ex201, a main body equipped with a set of operation keys
ex204, a voice output unit ex208 such as a speaker for outputting voices,
a voice input unit ex205 such as a microphone for inputting voices, a
recording medium ex207 for storing coded data or decoded data such as
data of moving pictures or still pictures shot by the camera, data of
received e-mails and moving picture data or still picture data, and a
slot unit ex206 for enabling the recording medium ex207 to be attached to
the cellular phone ex115. The recording medium ex207 is embodied as a
flash memory element, a kind of EEPROM (Electrically Erasable and
Programmable Read Only Memory) that is an electrically erasable and
rewritable nonvolatile memory, stored in a plastic case such as an SD
card.

[0150] Next, referring to FIG. 16, a description is given of the cellular
phone ex115. In the cellular phone ex115, a main control unit ex311 for
centrally controlling the display unit ex202 and each unit of the main
body having the operation keys ex204 is configured in a manner in which a
power supply circuit unit ex310, an operation input control unit ex304, a
picture coding unit ex312, a camera interface unit ex303, an LCD (Liquid
Crystal Display) control unit ex302, a picture decoding unit ex309, a
multiplexing/demultiplexing unit ex308, a recording/reproducing unit
ex307, a modem circuit unit ex306, and a voice processing unit ex305 are
interconnected via a synchronous bus ex313.

[0151] When a call-end key or a power key is turned on by a user
operation, the power supply circuit unit ex310 supplies each unit with
power from a battery pack, and activates the camera-equipped digital
cellular phone ex115 to make it into a ready state.

[0152] In the cellular phone ex115, the voice processing unit ex305
converts a voice signal received by the voice input unit ex205 in
conversation mode into digital voice data under the control of the main
control unit ex311 comprised of a CPU, a ROM, a RAM and others, the modem
circuit unit ex306 performs spread spectrum processing on it, and a
transmit/receive circuit unit ex301 performs digital-to-analog conversion
processing and frequency transformation processing on the data, so as to
transmit the resultant via the antenna ex201. Also, in the cellular phone
ex115, data received by the antenna ex201 in conversation mode is
amplified and performed of frequency transformation processing and
analog-to-digital conversion processing, the modem circuit unit ex306
performs inverse spread spectrum processing on the resultant, and the
voice processing unit ex305 converts it into analog voice data, so as to
output it via the voice output unit ex208.

[0153] Furthermore, when sending an e-mail in data communication mode,
text data of the e-mail inputted by operating the operation keys ex204 on
the main body is sent out to the main control unit ex311 via the
operation input control unit ex304. In the main control unit ex311, after
the modem circuit unit ex306 performs spread spectrum processing on the
text data and the transmit/receive circuit unit ex301 performs
digital-to-analog conversion processing and frequency transformation
processing on it, the resultant is transmitted to the base station ex110
via the antenna ex201.

[0154] When picture data is transmitted in data communication mode, the
picture data shot by the camera unit ex203 is supplied to the picture
coding unit ex312 via the camera interface unit ex303. When picture data
is not to be transmitted, it is also possible to display such picture
data shot by the camera unit ex203 directly on the display unit ex202 via
the camera interface unit ex303 and the LCD control unit ex302.

[0155] The picture coding unit ex312, which includes the moving picture
coding apparatus according to the present invention, performs compression
coding on the picture data supplied from the camera unit ex203 using the
coding method employed by the moving picture coding apparatus presented
in the above embodiment, so as to convert it into coded picture data, and
sends it out to the multiplexing/demultiplexing unit ex308. At this time,
the cellular phone ex115 sends voices received by the voice input unit
ex205 while the shooting by the camera unit ex203 is taking place, to the
multiplexing/demultiplexing unit ex308 as digital voice data via the
voice processing unit ex305.

[0156] The multiplexing/demultiplexing unit ex308 multiplexes the coded
picture data supplied from the picture coding unit ex312 and the voice
data supplied from the voice processing unit ex305 using a predetermined
method, the modem circuit unit ex306 performs spread spectrum processing
on the resulting multiplexed data, and the transmit/receive circuit unit
ex301 performs digital-to-analog conversion processing and frequency
transformation processing on the resultant, so as to transmit the
processed data via the antenna ex201.

[0157] When receiving, in data communication mode, moving picture file
data which is linked to a Web page or the like, the modem circuit unit
ex306 performs inverse spread spectrum processing on the received signal
received from the base station ex110 via the antenna ex201, and sends out
the resulting multiplexed data to the multiplexing/demultiplexing unit
ex308.

[0158] In order to decode the multiplexed data received via the antenna
ex201, the multiplexing/demultiplexing unit ex308 separates the
multiplexed data into a bitstream of picture data and a bitstream of
voice data, and supplies such coded picture data to the picture decoding
unit ex309 and such voice data to the voice processing unit ex305 via the
synchronous bus ex313.

[0159] Next, the picture decoding unit ex309, which includes the moving
picture decoding apparatus according to the present invention, decodes
the bitstream of the picture data using the decoding method paired with
the coding method shown in the above-mentioned embodiment so as to
generate moving picture data for reproduction, and supplies such data to
the display unit ex202 via the LCD control unit ex302. Accordingly,
moving picture data included in the moving picture file linked to a Web
page, for instance, is displayed. At the same time, the voice processing
unit ex305 converts the voice data into an analog voice signal, and then
supplies this to the voice output unit ex208. Accordingly, voice data
included in the moving picture file linked to a Web page, for instance,
is reproduced.

[0160] Note that the aforementioned system is not an exclusive example and
therefore that at least either the moving picture coding apparatus or the
moving picture decoding apparatus of the above embodiment can be
incorporated into a digital broadcasting system as shown in FIG. 17,
against the backdrop that satellite/terrestrial digital broadcasting has
been a recent topic of conversation. To be more specific, at a
broadcasting station ex409, a bitstream of video information is
transmitted, by radio waves, to a satellite ex410 for communications or
broadcasting. Upon receipt of it, the broadcast satellite ex410 transmits
radio waves for broadcasting, an antenna ex406 of a house equipped with
satellite broadcasting reception facilities receives such radio waves,
and an apparatus such as a television (receiver) ex401 and a set top box
(STP) ex407 decodes the bitstream and reproduces the decoded data. The
moving picture decoding apparatus as shown in the above-mentioned
embodiment can be implemented in the reproduction apparatus ex403 for
reading and decoding the bitstream recorded on a storage medium ex402
that is a recording medium such as a CD and a DVD. In this case, a
reproduced video signal is displayed on a monitor ex404. It is also
conceivable that the moving picture decoding apparatus is implemented in
the set top box ex407 connected to a cable ex405 for cable television or
the antenna ex406 for satellite/terrestrial broadcasting so as to
reproduce it on a television monitor ex408. In this case, the moving
picture decoding apparatus may be incorporated into the television, not
in the set top box. Or, a car ex412 with an antenna ex411 can receive a
signal from the satellite ex410, the base station ex107 or the like, so
as to reproduce a moving picture on a display device such as a car
navigation system ex413 mounted on the car ex412.

[0161] Furthermore, it is also possible to code a picture signal by the
moving picture coding apparatus presented in the above embodiment and to
record the resultant in a recording medium. Examples include a DVD
recorder for recording a picture signal on a DVD disc ex421 and a
recorder ex420 such as a disc recorder for recording a picture signal on
a hard disk. Moreover, a picture signal can also be recorded in an SD
card ex422. If the recorder ex420 is equipped with the moving picture
decoding apparatus presented in the above embodiment, it is possible to
reproduce a picture signal recorded on the DVD disc ex421 or in the SD
card ex422, and display it on the monitor ex408.

[0162] As the configuration of the car navigation system ex413, the
configuration without the camera unit ex203, the camera interface unit
ex303 and the picture coding unit ex312, out of the configuration shown
in FIG. 16, is conceivable. The same is applicable to the computer ex111,
the television (receiver) ex401 and the like.

[0163] Concerning the terminals such as the cellular phone ex114, a
transmitting/receiving terminal having both an encoder and a decoder, as
well as a transmitting terminal only with an encoder, and a receiving
terminal only with a decoder are possible as forms of implementation.

[0164] As stated above, it is possible to employ the moving picture coding
method and the moving picture decoding method presented in the above
embodiments into any one of the above-described devices and systems.
Accordingly, it becomes possible to achieve the effect described in the
aforementioned embodiments.

[0165] It should also be noted that the present invention is not limited
to the above embodiments, and many variations or modifications thereof
are possible without departing from the scope of the invention.

[0166] Note that each function block in the block diagrams shown in FIGS.
3 and 9 can be realized as an LSI that is a typical integrated circuit
apparatus. Such LSI may be incorporated in one or plural chip form (e.g.
function blocks other than a memory may be incorporated into a single
chip). Here, LSI is taken as an example, but, it can be called "IC",
"system LSI", "super LSI" and "ultra LSI" depending on the integration
degree.

[0167] The method for incorporation into an integrated circuit is not
limited to the LSI, and it may be realized with a private line or a
general processor. After manufacturing of LSI, a Field Programmable Gate
Array (FPGA) that is programmable or a reconfigurable processor that can
reconfigure the connection and settings for the circuit cell in the LSI
may be utilized.

[0168] Furthermore, along with the arrival of technique for incorporation
into an integrated circuit that replaces the LSI owing to a progress in
semiconductor technology or another technique that has derived from it,
integration of the function blocks may be carried out using the
newly-arrived technology. Bio-technology may be cited as one of the
examples.

[0169] Among the function blocks, only a unit for storing data to be coded
or decoded may be constructed separately without being incorporated in a
chip form.

INDUSTRIAL APPLICABILITY

[0170] As described above, the moving picture coding method and the moving
picture decoding method according to the present invention are useful as
methods for coding pictures that make up a moving picture so as to
generate a coded stream and for decoding the generated coded stream, in
devices such as a cellular phone, a DVD device and a personal computer.